When the Goblins were in their early stages of life on their native Isle of Kezan, they were simple, unintelligent beings. At some point, they were enslaved by trolls and forced to work in mines.

While the Goblins were mining away at the core of Kazan, they came across a new mineral they called Kaja'mite. The trolls began using the mineral in their voodoo rituals and discovered some magical properties within it, so they made the Goblins focus on mining the ore.

After a while, the Goblins learned that the mineral was more powerful than the trolls realized, so they started hording it deep within the mines where no troll ever went.

But the ore was still mor epowerful than even the Goblins realized; as the horde of ore grew, the magical properties of the ore became more potent and began increasing the level of intelligence in the Goblins. They were getting smarter and smarter every day, and they began preparing to overthrow their troll masters.

Eventually, they reversed the rolls between them and their former captives, and they put the trolls to work mining the Kaja'mite for the Goblins, keeping close watch on the mines to make sure the trolls didn't pull the same thing on them.

With their super heightened intelligence, the Goblins began developing and building technologies and engineering feats that would make Gelbin Mekkatorque salivate. For a long time, there was no technologies that could even hope to rival that of the Goblins.

However, it turned out that the enchanted properties of the Kaja'mite was not limitless, and it began to run out. They began scouring the entire world for any Kaja'mite deposits, but eventually the precious ore ran dry. This was about 500 years before the First War.

This caused the Goblins' intelligence to somewhat recede, not anywhere near what it was before their exposure, but it was enough to stagnate their technological evolution, and even become worse than most basic devices. But the Goblins are very proud creatures and refused to admit to their devolution, so they continued to build and create as if the Kaja'mite hadn't run out.

Which brings us to the Goblin technology of today. Constantly striving to match a now unobtainable level of genius, not to mention having competition coming from the Gnomes and Dwarves, the Goblins are pumping out these technologies that are very precarious and prone to high rates of failure.

TL;DR The Goblins got super smart because of a magic ore, made lots of cool shit, the ore ran out, they dumbed down a bit, and now try and fail to match their cool shit from before.

I love the WoW lore. There are so many individuals throughout the history, and they all cross each other at some point. I recommend giving the wowwiki site a read. I go there every time I come across something in game that peaks my curiosity.

Goblins are my favorite race ever since they became playable. Here's another bit of trivia on them: When the Goblins were found by Thrall and were welcomed into the Horde, they made their base of operations in Azshara, just north of Orgrimmar. To show their appreciation and dedication to the Horde, they terraformed the coast of Azshara into the symbol of the Horde.

The blood elves, discovering what the draenei were planning, sabotaged the dimensional engines of the vessel. When the draenei activated it, the engine malfunctioned and sent the Exodar hurtling out of control through the Twisting Nether

Goblin engineering is all about finding the balance between extremely powerful explosions and making your devices strong enough to harness the power of the explosions.

Who am I kidding, its about making the explosions so big nothing can stop them.

Most goblin crashes aren't due to malfunction, they are caused by trying to go faster/higher/kill something with a bigger boom/look even cooler. At some point the hull of the ship just can't hold back all the awesome.